一株耐受低pH光滑球拟酵母RT-6的生理特性

Physiological characteristics of a low-pH tolerant strain Torulopsis glabrata RT-6

摘要:

摘要：【目的】 研究一株耐受pH 1.91的光滑球拟酵母 (Torulopsis glabrata) RT-6的生理特性。【方法】在不同的pH条件下，对比分析原菌CCTCC M202019和突变株RT-6胞内pH、胞内ATP水平、H+-ATPase酶活、膜脂肪酸组成和聚磷酸盐含量等生理学特性的差异。【结果】与原菌比较，突变株RT-6：(1)生物量和丙酮酸产量分别提高了60.6 %和85.4 % (56 h)；(2) 在胞外pH5.0、4.5、4.0时，胞内pH极显著高于原菌；(3)胞内ATP、H+-ATP

Abstract:

Abstract: [Objective] With the aim of elucidating the physiological characteristics of a low-pH tolerant strain Torulopsis glabrata RT-6. [Methods] The intracellular pH, ATP level, the membrane bound H+-ATPase activity, the membrane fatty acid composition and the intracellular polyphosphate content of the parent strain CCTCC M202019 and the mutant strain RT-6 were determined and compared under different pH conditions. [Results] Compared to that of the parent strain, the cell growth and pyruvate concentration of the mutant strain RT-6 were increased by 60.6 % and 85.4 % (56 h), respectively. Similarly, the strain RT-6 had higher intracellular pH compared to the control strain at external pH5.0, 4.5, and 4.0. The ATP content, the membrane bound H+-ATPase activity and the intracellular polyphosphate content of the mutant strain RT-6 were increased by 11.7 %, 13.6 %, and 3.5 % at external pH 5.5, while at external pH 4.0, increased by 61 %, 38.6 %, and 30.8 % , respectively. Furthermore, the mutant strain RT-6 exhibited higher content of the unsaturated fatty acids and higher membrane fluidity. [Conclusion] Discharging more intracellular H+ and inhibiting the intracellular H+ production contributed to the strain RT-6’s higher intracellular pH, and therefore the acid tolerance.